Electric thread dryer



g- 969 P. A. w. JURSCHEWITZ 3,461,252

ELECTRIC THREAD DRYER Filed Sept. 2, 19 66 INVENTOR: v PAUL A. W J'URSCHE'W/TZ Ross gag Attorney 3,461,262 ELECTRIC THREAD DRYER Paul Artur Waldemar Jurschewitz, 43 Rue du Poteau, Paris, 18e, France Filed Sept. 2, 1966, Ser. No. 576,980 Int. Cl. H05b 5/02 US. Cl. 21.9-10.61 5 Claims ABSTRACT F THE DISCLOSURE Thread-drying apparatus wherein two parallel metallic disks, rotatable about a common axis, are provided with respective sets of peripherally spaced conductor rods, the two rods being interleaved to define a polygonal drum profile; the two disks and their respective rods are capacitively energized to develop a high-frequency field across adjoining rods for drying filamentary material wrapped around the drum.

The present invention relates to an apparatus for the drying of wet threads or other filamentary articles of low electrical conductivity capable of being moved, singly or in bunches, over the periphery of a rotatable heating drum.

The general object of this invention is to provide a heating drum for this purpose having means for generating along its periphery a high-frequency electric field to induce heating currents in the articles to be dried, the electrical connections to the drums being such as not to interfere with its rotation.

This object is realized, in conformity with my present invention, by the provision of a drum having two conductive and mutually insulated end disks each carrying a peripheral array of conductor rods extending axially toward the other end disk, the rods of the two arrays being alternately interleaved in partly overlapping relationship so that their overlapping portions define a polygon of preferably not less than four rods (two from each array) per quadrant. These rods are energized from a source of highfrequency voltage in a circuit in which the two end disks are capacitively coupled to the high-frequency source so as to dispense with the need for any physical connection thereto. More specifically, I prefer to use for this purpose a pair of stationary condenser plates which bracket the drum and are closely juxtaposed with the respective end disks while being themselves connected across the voltage source.

The invention will be described in greaterdetail with reference to the drawing in which:

FIG. 1 is an elevational view, in axial section and partly diagrammatic, of a drying apparatus comprising a drum according to the invention; and

FIG. 2 is a cross-sectional view taken on the line II-LI of FIG. 1.

The apparatus shown in the drawing comprises a shaft 4 of nonconductive (preferably ceramic) material journaled via ball bearings 14 and 15 in a pair of fixed supports 16, 17 which are part of a machine frame not further illustrated. Shaft 4 carries a pair of metal disks 3 and 5 each supporting a peripheral array of conductor rods 1 and 2, respectively, these rods having a length slightly less than the axial spacing of the disks 3 and 5. As best seen in FIG. 2, the two sets of rods 1 and 2 are alternately interleaved with uniform angular spacing which, in the presence of eight rods per array as shown, amounts to a peripheral separation of 22 /2 for the corners of the polygon defined thereby. The disks 3 and 5 have bosses 8 and 3,461,262 Patented Aug. 12, 1969 9 which are keyed to the shaft 4 and extend axially outwardly through center apertures in a pair of circularly annular condenser plates 6 and 7 respectively confronting these disks; the presence of the bosses 8 and 9 in closely spaced relationship with reference to the inner peripheries of the annular plates 6, 7 increases the capacitance of the two condensers 3, 6 and 5, 7. The plates 6 and 7 are connected via conductors 10 and 11 to respective terminals 12 and 13, these terminals and conductors forming part of an energizing circuit including a high-frequency oscillator 20 in series with a switch 21. As shown in FIG. 1, oscillator 20 may be common to a plurality of such energizing circuits connected in parallel thereaoross and leading to a set of drying drums, all similar to the one illustrated, which may be mounted on the same shaft 4.

In operation, one or more threads 18 are wound partly around the drum and a deflecting roller 19 (omitted in FIG. 1) so as to span an arc of approximately along the drum periphery. As the thread 18 moves in the direction of the arrows shown in FIG. 2, the drum rotates with its shaft 4 at the same peripheral speed, either under fric tional entrainment by the thread or under the power of a motor not shown. The high-frequency field set up across the conductor rods 1 and 2 along the polygonal sectors a h, FIG. 2, induces the flow of heating currents in the threads 18 contacting these rods. This results in a rapid and efiicient drying of the initially wet threads.

The spacing between condenser plates 3, 6 and 5, 7 should be so chosen that the resulting capacitance of each of these condensers is a multiple of that existing between the two arrays of rods 1, 2 preferably exceeding the latter capacitance by at least a factor of 100. Thus, for example, the capacitance of the condenser 3, 6 as well as that of the condenser 5, 7 may be on the order of 10 pf. While that between the rods may be around 0.1 pf.

The plates 6,7 may be fixedly secured to the machine frame, with the necessary mutual insulation, by any convenient means not illustrated.

I claim:

1. An apparatus for drying filamentary articles of low electrical conductivity, comprising a drum with a pair of conductive and mutually insulated end disks each carrying a peripheral array of conductor rods extending axially toward the other end disk in overlapping relationship with the rods carried by said other end disk, the rods of the two arrays being alternately interleaved; shaft means supporting said end disks for joint rotation about a common axis; a source of high-frequency voltage; and condenser means including said end disks for capacitively connecting said two end disks across said source, thereby generating a high-frequency electric field between the interleaved rods of said arrays to heat a filamentary article passing around the polygonal periphery of the rotating drum defined by the overlapping rod portions, said condenser means comprising a pair of parallel metal plates bracketing said drum at short axial distances from the respective end disks.

2. An apparatus as defined in claim 1 wherein said shaft means comprises a throughgoing shaft of nonconductive material journaled in a support, said plates being fixed with reference to said support.

3. An apparatus as defined in claim 1 wherein said plates have central bores traversed with clearance by said shaft means, said end disks being provided with integral conductive bosses surrounding said shaft means and penetrating into said bores.

4. An apparatus as defined in claim 1 wherein the spacing between said end disks and the respective plates is so 3 s 4.- close as to provide a capacitance therebetween exceeding 2,492,187 12/1949 Rusca 219-10.61 the capacitance between said two arrays of rods by at least 2,679,573 5/ 1954 Newhouse 21910.81 X a factor of 100.

5. An apparatus as defined in claim 1 wherein the num- FOREIGN PATENTS ber of rods in each array is at least two per quadrant. 5 1,452,792 8/1966 France.

References Cited JOSEPH V. TRUHE, Primary Examiner UNITED STATES PATENTS L. H. BENDER, Assistant Examiner 2,248,840 7/1941 Wilkoff 219--10.61 X US. Cl. X.R.

2,319,174 5/1943 Wilson 219-10.81 X 10 219 10 

